The following invention relates to systems for retracting a window shade from a lower position occluding a greater portion of a window to an upper position occluding less of the window, and vice versa. More particularly, this invention relates to systems for maintaining cords of a window shade in the proper position to support the window shade at a desired height and with the cord maintained in a fashion free of susceptibility to jamming, tangling or other damage.
Windows are often fitted with shades or blinds to control the passage of light through the windows. Shades are generally the category of window covering which provides a continuous layer of fabric or other material which can be raised to allow light to pass through the window or lowered to block, at least partially, light passing through the window. Blinds are generally referred to as a related device which when in a lowered position only partially blocks the passage of light through the window, in either a fixed or adjustable xe2x80x9cVenetian blindxe2x80x9d configuration.
For both shades and blinds, together referred to as window shades, numerous prior art devices are known to raise, lower and control the height of the window shade within the frame surrounding the window. Many such window shade height adjustment control systems include one or more cords with the cords generally coupled between a top edge and a bottom edge of the window shade. Shortening of the cord raises the window shade and lengthening of the cord lowers the window shade.
When a portion of the cord between the top edge and the bottom edge of the window shade is shortened, this cord must go somewhere, typically dangling freely outside of the window shade. This excess cord can pose a risk of serious injury to small children or animals, resulting in numerous attempts in the prior art to collect this excess cord extending outside of the window shades. For instance, see U.S. Pat. Nos. 4,271,893, 5,279,473, 5,354,011 and 5,762,281.
This invention provides a retractable window shade with height adjustment control that utilizes cords for such height adjustment control but which largely contains and manages the cords internally within the various structures of the window shade. The cords pose no risk of injury and are maintained in a fashion which prevents damage to the cords and disabling of the retraction and height adjustment control mechanisms of the window shade. The window shade of this invention includes a shade element extending between a top edge and a bottom edge. At least one cord is provided with an upper end adjacent the top edge and with a lower end adjacent a portion of the shade element spaced below the top edge, typically adjacent the bottom edge of the shade element.
A cord retainer is located along the cord, typically at the lower end of the cord and adjacent the bottom edge of the shade element. The retainer is preferably configured as a spool which is rotatably supported relative to the bottom edge of the shade element. The spool can thus rotate to gather the cord onto the spool and retain portions of the cord which are not needed as the bottom edge of the shade element is raised up towards the top edge of the shade element, such as when the window shade is raised.
A cord retractor is provided to bias the retainer toward having the cord entirely loaded upon the spool. This cord retractor is selectively activatable, so that when the retractor is activated the spool or other retainer can gather the cord onto the spool, and when deactivated the spool or other retainer does not draw the cord onto the retainer and the height of the window shade is held constant.
The selective activatability of the retractor can be provided, such as with a cord brake to hold the cord relative to the spool or other retainer and prevent the spool or other retainer from drawing more of the cord onto the spool. In a preferred form of the invention, the retractor biases the spool or other retainer toward having more of the cord upon the retainer. The retractor is configured to include a spring which stores energy when the cord is largely off of the spool or other retainer and releases energy to cause the spool or other retainer to rotate or otherwise be loaded with the cord when a large portion of the cord is off of the spool or other retainer, such as when the window shade is in a lower position with a large portion of the cord used to extend between the top edge and the bottom edge of the shade element.
The cord brake or other selectively activatable retractor activation mechanism is preferably manually adjustable by pushing buttons adjacent the bottom edge of the shade element. When these buttons are depressed, the cord brake is released and the retainer is biased to draw up the cord onto the retainer. If manual forces are simultaneously applied to the bottom edge of the shade element to lift the bottom edge of the shade element, the cord is retracted onto the retainer as the bottom edge of the shade element is raised.
Alternatively, if the bottom edge of the shade element is pulled down while the button of the cord brake or other manual control for the selectively activatable retractor is activated, the biasing forces on the retainer can be overcome by the user and the bottom edge of the shade element pulled down away from the top edge, thereby increasing energy stored in the retractor for later gathering of cord when the window shade is later raised. When the buttons of the cord brake, or other selectively activatable retractor, are released the cord brake is activated and the cord retractor deactivated so that the window shade can maintain a stationary position where it is left.
Accordingly, a primary object of the present invention is to provide a window shade which includes at least one cord extending between a top edge of the shade element and a portion of the shade element below the top edge, and with excess portions of the cord retained safely for later use.
Another object of the present invention is to provide a retractable window shade which can be readily manually raised and lowered without requiring the handling of cords manually.
Another object of the present invention is to provide a window shade which can be readily raised and lowered without cords dangling freely where they can be damaged or pose a safety hazard.
Another object of the present invention is to provide a retractable window shade which can have a height thereof readily manually adjusted to a desired height.
Another object of the present invention is to provide a retractable window shade which exhibits highly reliable performance.
Other further objects of the present invention will become apparent from a careful reading of the included drawing figures, the claims and detailed description of the invention.